/*
 *  Copyright 2008 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.mybatis.generator.plugins;

import static org.mybatis.generator.internal.util.JavaBeansUtil.getGetterMethodName;

import java.util.Iterator;
import java.util.List;

import org.mybatis.generator.api.PluginAdapter;
import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.dom.OutputUtilities;
import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;
import org.mybatis.generator.api.dom.java.JavaVisibility;
import org.mybatis.generator.api.dom.java.Method;
import org.mybatis.generator.api.dom.java.Parameter;
import org.mybatis.generator.api.dom.java.TopLevelClass;

/**
 * This plugin adds equals() and hashCode() methods to the generated model
 * classes. It demonstrates the process of adding methods to generated classes
 * <p>
 * The <tt>equals</tt> method generated by this class is correct in most cases,
 * but will probably NOT be correct if you have specified a rootClass - because
 * our equals method only checks the fields it knows about.
 * <p>
 * Similarly, the <tt>hashCode</tt> method generated by this class only relies
 * on fields it knows about. Anything you add, or fields in a super class will
 * not be factored into the hash code.
 * 
 * @author Jeff Butler
 * 
 */
public class EqualsHashCodePlugin extends PluginAdapter {

	public EqualsHashCodePlugin() {
	}

	/**
	 * This plugin is always valid - no properties are required
	 */
	public boolean validate(List<String> warnings) {
		return true;
	}

	@Override
	public boolean modelBaseRecordClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
		List<IntrospectedColumn> columns;
		if (introspectedTable.getRules().generateRecordWithBLOBsClass()) {
			columns = introspectedTable.getNonBLOBColumns();
		} else {
			columns = introspectedTable.getAllColumns();
		}

		generateEquals(topLevelClass, columns, introspectedTable);
		generateHashCode(topLevelClass, columns, introspectedTable);

		return true;
	}

	@Override
	public boolean modelPrimaryKeyClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
		generateEquals(topLevelClass, introspectedTable.getPrimaryKeyColumns(), introspectedTable);
		generateHashCode(topLevelClass, introspectedTable.getPrimaryKeyColumns(), introspectedTable);

		return true;
	}

	@Override
	public boolean modelRecordWithBLOBsClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {
		generateEquals(topLevelClass, introspectedTable.getAllColumns(), introspectedTable);
		generateHashCode(topLevelClass, introspectedTable.getAllColumns(), introspectedTable);

		return true;
	}

	/**
	 * Generates an <tt>equals</tt> method that does a comparison of all fields.
	 * <p>
	 * The generated <tt>equals</tt> method will be correct unless:
	 * <ul>
	 * <li>Other fields have been added to the generated classes</li>
	 * <li>A <tt>rootClass</tt> is specified that holds state</li>
	 * </ul>
	 * 
	 * @param topLevelClass
	 *            the class to which the method will be added
	 * @param introspectedColumns
	 *            column definitions of this class and any superclass of this
	 *            class
	 * @param introspectedTable
	 *            the table corresponding to this class
	 */
	protected void generateEquals(TopLevelClass topLevelClass, List<IntrospectedColumn> introspectedColumns,
			IntrospectedTable introspectedTable) {
		Method method = new Method();
		method.setVisibility(JavaVisibility.PUBLIC);
		method.setReturnType(FullyQualifiedJavaType.getBooleanPrimitiveInstance());
		method.setName("equals"); //$NON-NLS-1$
		method.addParameter(new Parameter(FullyQualifiedJavaType.getObjectInstance(), "that")); //$NON-NLS-1$
		if (introspectedTable.isJava5Targeted()) {
			method.addAnnotation("@Override"); //$NON-NLS-1$
		}

		context.getCommentGenerator().addGeneralMethodComment(method, introspectedTable);

		method.addBodyLine("if (this == that) {"); //$NON-NLS-1$
		method.addBodyLine("return true;"); //$NON-NLS-1$
		method.addBodyLine("}"); //$NON-NLS-1$

		method.addBodyLine("if (that == null) {"); //$NON-NLS-1$
		method.addBodyLine("return false;"); //$NON-NLS-1$
		method.addBodyLine("}"); //$NON-NLS-1$

		method.addBodyLine("if (getClass() != that.getClass()) {"); //$NON-NLS-1$
		method.addBodyLine("return false;"); //$NON-NLS-1$
		method.addBodyLine("}"); //$NON-NLS-1$

		StringBuilder sb = new StringBuilder();
		sb.append(topLevelClass.getType().getShortName());
		sb.append(" other = ("); //$NON-NLS-1$
		sb.append(topLevelClass.getType().getShortName());
		sb.append(") that;"); //$NON-NLS-1$
		method.addBodyLine(sb.toString());

		boolean first = true;
		Iterator<IntrospectedColumn> iter = introspectedColumns.iterator();
		while (iter.hasNext()) {
			IntrospectedColumn introspectedColumn = iter.next();

			sb.setLength(0);

			if (first) {
				sb.append("return ("); //$NON-NLS-1$
				first = false;
			} else {
				OutputUtilities.javaIndent(sb, 1);
				sb.append("&& ("); //$NON-NLS-1$
			}

			String getterMethod = getGetterMethodName(introspectedColumn.getJavaProperty(),
					introspectedColumn.getFullyQualifiedJavaType());

			if (introspectedColumn.getFullyQualifiedJavaType().isPrimitive()) {
				sb.append("this."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("() == "); //$NON-NLS-1$
				sb.append("other."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("())"); //$NON-NLS-1$
			} else {
				sb.append("this."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("() == null ? other."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("() == null : this."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("().equals(other."); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("()))"); //$NON-NLS-1$
			}

			if (!iter.hasNext()) {
				sb.append(';');
			}

			method.addBodyLine(sb.toString());
		}

		topLevelClass.addMethod(method);
	}

	/**
	 * Generates a <tt>hashCode</tt> method that includes all fields.
	 * <p>
	 * Note that this implementation is based on the eclipse foundation hashCode
	 * generator.
	 * 
	 * @param topLevelClass
	 *            the class to which the method will be added
	 * @param introspectedColumns
	 *            column definitions of this class and any superclass of this
	 *            class
	 * @param introspectedTable
	 *            the table corresponding to this class
	 */
	protected void generateHashCode(TopLevelClass topLevelClass, List<IntrospectedColumn> introspectedColumns,
			IntrospectedTable introspectedTable) {
		Method method = new Method();
		method.setVisibility(JavaVisibility.PUBLIC);
		method.setReturnType(FullyQualifiedJavaType.getIntInstance());
		method.setName("hashCode"); //$NON-NLS-1$
		if (introspectedTable.isJava5Targeted()) {
			method.addAnnotation("@Override"); //$NON-NLS-1$
		}

		context.getCommentGenerator().addGeneralMethodComment(method, introspectedTable);

		method.addBodyLine("final int prime = 31;"); //$NON-NLS-1$
		method.addBodyLine("int result = 1;"); //$NON-NLS-1$

		StringBuilder sb = new StringBuilder();
		boolean hasTemp = false;
		Iterator<IntrospectedColumn> iter = introspectedColumns.iterator();
		while (iter.hasNext()) {
			IntrospectedColumn introspectedColumn = iter.next();

			FullyQualifiedJavaType fqjt = introspectedColumn.getFullyQualifiedJavaType();

			String getterMethod = getGetterMethodName(introspectedColumn.getJavaProperty(), fqjt);

			sb.setLength(0);
			if (fqjt.isPrimitive()) {
				if ("boolean".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
					sb.append("result = prime * result + ("); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("() ? 1231 : 1237);"); //$NON-NLS-1$
					method.addBodyLine(sb.toString());
				} else if ("byte".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
					sb.append("result = prime * result + "); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("();"); //$NON-NLS-1$
					method.addBodyLine(sb.toString());
				} else if ("char".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
					sb.append("result = prime * result + "); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("();"); //$NON-NLS-1$
					method.addBodyLine(sb.toString());
				} else if ("double".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
					if (!hasTemp) {
						method.addBodyLine("long temp;"); //$NON-NLS-1$
						hasTemp = true;
					}
					sb.append("temp = Double.doubleToLongBits("); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("());"); //$NON-NLS-1$
					method.addBodyLine(sb.toString());
					method.addBodyLine("result = prime * result + (int) (temp ^ (temp >>> 32));"); //$NON-NLS-1$
				} else if ("float".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
					sb.append("result = prime * result + Float.floatToIntBits("); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("());"); //$NON-NLS-1$
					method.addBodyLine(sb.toString());
				} else if ("int".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
					sb.append("result = prime * result + "); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("();"); //$NON-NLS-1$
					method.addBodyLine(sb.toString());
				} else if ("long".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
					sb.append("result = prime * result + (int) ("); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("() ^ ("); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("() >>> 32));"); //$NON-NLS-1$
					method.addBodyLine(sb.toString());
				} else if ("short".equals(fqjt.getFullyQualifiedName())) { //$NON-NLS-1$
					sb.append("result = prime * result + "); //$NON-NLS-1$
					sb.append(getterMethod);
					sb.append("();"); //$NON-NLS-1$
					method.addBodyLine(sb.toString());
				} else {
					// should never happen
					continue;
				}
			} else {
				sb.append("result = prime * result + (("); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("() == null) ? 0 : "); //$NON-NLS-1$
				sb.append(getterMethod);
				sb.append("().hashCode());"); //$NON-NLS-1$
				method.addBodyLine(sb.toString());
			}
		}

		method.addBodyLine("return result;"); //$NON-NLS-1$

		topLevelClass.addMethod(method);
	}
}
